Search



Go Back   Third Generation F-Body Message Boards > Tech Boards > Tech / General Engine
Register Forgot Password?

Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Sponsored by Weld Racing
Click Here

Welcome to ThirdGen.org!
Welcome to ThirdGen.org.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!


Reply
 
Thread Tools Search this Thread
Old 03-09-2012, 08:11 PM   #1
Supreme Member
 
zraffz's Avatar
 
Join Date: Mar 2009
Location: Sussex County, NJ
Posts: 1,262
Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42

Classifieds Rating: (0)
Vortec 350 cam selection?

I recently purchased a S10 with a 305/200-4R in it (very clean truck for a very fair price). Clearly could see it had 5.0 stamped on the block but had no intention of keeping that motor.

I have a very high mileage (250,000+ miles) vortec 350 laying around that still ran very strong. Haven't taken it apart yet but plan on having the crank cleaned, new crank/rod/cam bearings, hope I can get away with just honing and buying rings. I have low mileage LS7 lifters and 1.5 roller rockers sitting around.
Will be having the heads checked out and machined to fit stronger springs.

I don't want to turn this thing past 6,000 RPM. Been eyeing up Comp Cams XR282HR (http://www.compcams.com/Company/CC/c...?csid=189&sb=2) 230/236 .510"/.520" 110LSA. Anybody have a better cam selection?

Not looking for anything insane since the truck is relatively lightweight to begin with and I am building the Z28. Want to keep the converter stall under 2,500. Figure with a stock bottom end I can squeak out an easy 350hp/350tq at the crank.
zraffz is offline vBGarage Page   Reply With Quote
Old 03-09-2012, 08:41 PM   #2
Member
 
Join Date: Mar 2010
Location: Ft Hood Texas
Posts: 218
Car: 87 Trans am
Engine: LT-1
Transmission: 4L60E
Axle/Gears: soon to be 3:42

Classifieds Rating: (0)
Re: Vortec 350 cam selection?

everything ive been told the comp cam 268 and 274 are really good on the vortec engines. the 282 might have too much lift for what you are looking for, im sure someone a lil more knowledgeable will chim in, but from my experience the 268 and 274 will knock a 350 vortec well into the 300-350hp range
midge54 is offline vBGarage Page   Reply With Quote
Old 03-09-2012, 08:54 PM   #3
Supreme Member
 
zraffz's Avatar
 
Join Date: Mar 2009
Location: Sussex County, NJ
Posts: 1,262
Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42

Classifieds Rating: (0)
Re: Vortec 350 cam selection?

Quote:
Originally Posted by midge54 View Post
everything ive been told the comp cam 268 and 274 are really good on the vortec engines. the 282 might have too much lift for what you are looking for, im sure someone a lil more knowledgeable will chim in, but from my experience the 268 and 274 will knock a 350 vortec well into the 300-350hp range
As far as I can figure the 282 would be good; would require a little machining on the heads but nothing expensive.
From what I understand the vortec heads stop breathing at around .530" lift, I can keep it just under that and have a very hard hitting motor from 2500-5800 RPM.
zraffz is offline vBGarage Page   Reply With Quote
Old 03-09-2012, 09:30 PM   #4
Member
 
alvanwie's Avatar
 
Join Date: Oct 2005
Location: Dyer, In
Posts: 328
Car: 91 Camaro RS
Engine: 355 Vortec
Transmission: 700r4
Axle/Gears: 3.42

Classifieds Rating: (0)
Re: Vortec 350 cam selection?

I would not go larger than the xr276hr with near stock vortecs ( modified for lift only). All the simulations I have done says thats about it. 268 is also very good in a vortec.

Should put you in the 375-400 fwhp range. Would also recommend flat top pistons to up the compression with this much cam.
__________________
1991 Camaro RS [click for pictures]
Comp XR269HR-12 cam, GM Intake 12496820
454 TBI, Vortec Heads
Hypereutectic Pistons 10.3:1
Crane 10309-1 Valve Springs/Retainers
Pacesetter Ceramic Coated headers
CGS Subframe Connectors, Jegster Rollbar
alvanwie is offline vBGarage Page   Reply With Quote
Old 03-10-2012, 04:15 AM   #5
Supreme Member
 
Join Date: Dec 2005
Location: Macon, GA
Posts: 6,063
Car: 1992 Camaro RS
Engine: Vortec headed 355, xe262
Transmission: T56
Axle/Gears: 9-bolt 3.70

Classifieds Rating: (3)
Send a message via AIM to InfernalVortex
Re: Vortec 350 cam selection?

xr282 is a pretty big cam. Xr276 is about the sweet spot. Makes around 350-400fwhp depending on the dyno/math/etc method you use, makes decent vacuum, and gets decent gas mileage. It's good for a 12 second car in an F-body. Beyond that the heads just cant support the power band any farther, and you just give up low end, gas mileage, and streetability for very little top end gain.

Vortec heads tank at about .500 lift. Doesnt mean you need to stay below that but it does mean you dont really help yourself by going higher. All you do is make yourself spend more money on valve springs.

If you want a slightly more affordable option that's proven to get you to the 350fwhp range easy, you can try the LT4 Hotcam. They go with vortecs like peanut butter and jelly. And you help yourself if you want to get the heads machined for better valve springs and have the guides machined down, but if you dont want to do that you can run it with some GM Ls2/LS3/LS6 "yellow" beehive springs with Comp 787-16 retainers. These springs are a pretty good match with that cam, but you have to balance spring pressure with valve lift, so that means you're probably better off going with 1.5 rockers with the hotcam, and that means .500/.500 lift instead of .525/.525 as teh specs say on it. If you go with some aftermarket beehive springs from comp that's not an issue anymore. But as much as those cost you may as well just get an xr276.
__________________

Last edited by InfernalVortex; 03-10-2012 at 04:21 AM.
InfernalVortex is offline vBGarage Page   Reply With Quote
Old 03-19-2012, 04:28 PM   #6
Supreme Member
 
zraffz's Avatar
 
Join Date: Mar 2009
Location: Sussex County, NJ
Posts: 1,262
Car: 1994 Z28
Engine: 355 LT1
Transmission: T56
Axle/Gears: 3.42

Classifieds Rating: (0)
Re: Vortec 350 cam selection?

Went with the CC XR276HR (08-423-8).
Does anybody have a recommendation for springs/retainers and studs?
Would it be cheaper to have the heads machined to fit the wider diameter springs or just get the narrower more expensive double hive springs that fit w/o machining?

Last edited by zraffz; 03-19-2012 at 04:36 PM.
zraffz is offline vBGarage Page   Reply With Quote
Old 03-19-2012, 09:24 PM   #7
Supreme Member
 
skinny z's Avatar
 
Join Date: Dec 2005
Location: Ontario, Canada
Posts: 3,369
Car: 86 Sport Coupe

Classifieds Rating: (0)
Re: Vortec 350 cam selection?

Quote:
Originally Posted by zraffz View Post
Went with the CC XR276HR (08-423-8).
Does anybody have a recommendation for springs/retainers and studs?
Would it be cheaper to have the heads machined to fit the wider diameter springs or just get the narrower more expensive double hive springs that fit w/o machining?
That's my current cam in a Vortec headed 350.
My suggestions are (in no particular order):
A "beehive" style spring (1.3" od) with a rating suitable for that cam; in my case I used a Comp Cams 26918 spring with the appropriate retainer. You may need an offset lock (.050") so as to get the proper installed height (I did). The 26918 (and 26915) spring will drop in without any machining to the valve spring pocket. There are other options besides the Comp spring. That's something you'll have to search for. FYI; the beehives are not double springs.
Screw-in studs for sure.
Guide plates are an option or you could go with a self-aligning rocker. The rocker stud bosses will have to be machined accordingly.
I'd also invest in some decent push rods although I ran mine with the Comp Magnum series which is middle of the road.
CHECK ALL OF YOUR CLEARENCES! Retainer to seal, coil bind, etc.
skinny z is offline vBGarage Page   Reply With Quote
Old 03-19-2012, 09:24 PM
ThirdGen
1992 Camaro




Paid Advertisement


Reply

Go Back   Third Generation F-Body Message Boards > Tech Boards > Tech / General Engine

Tags
2004r, 268, 350, 500, cam, comp, fit, good, heads, hot, lift, ls3, selection, stall, vortec
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

 


1982 Camaro '82 || 1983 Camaro '83 || 1984 Camaro '84 || 1985 Camaro '85 || 1986 Camaro '86 || 1987 Camaro '87 || 1988 Camaro '88 || 1989 Camaro '89 || 1990 Camaro '90 || 1991 Camaro '91 || 1992 Camaro '92


All times are GMT -5. The time now is 02:39 AM.


Powered by vBulletin® Version 3.7.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.5.2
All content copyright 1997 - 2014 ThirdGen.org. All rights reserved. No part of this website may be reproduced without the expressed, documented, and written consent of ThirdGen.org's Administrators.

Emails & Contact Details